1. Field of the Invention
The invention relates to a vacuum cleaning tool, in particular, for a vacuum cleaning device such as a vacuum cleaner or the like. The vacuum cleaning tool comprises a rotatingly driven working tool and has a housing with a bottom plate and a working slot formed in the bottom plate. The working tool that is rotatably supported in the housing acts through the working slot onto the surface to be cleaned on. The vacuum cleaning tool comprises an air turbine arranged in a turbine chamber of the housing and has axial end faces forming together with the sidewalls of the turbine chamber a gap, respectively. The turbine drives the working tool by means of a drive connection. In one turbine chamber wall of the turbine chamber, a first intake window for a driving suction air stream and a second intake window for a partial suction air stream are provided, wherein the driving suction air stream is supplied on one side of the rotational axis of the turbine to the peripheral turbine surface and wherein the partial suction air stream enters the turbine chamber on the opposite side of the rotational axis of the turbine.
2. Description of the Related Art
US-2002-0120999-A1 discloses a vacuum cleaning tool where the air turbine is not only loaded by a driving air stream on one side of the rotational axis of the turbine but, in addition, on the other side of the rotational axis a partial suction air stream is provided that is also directed onto the periphery of the turbine. The driving suction air stream rotates the air turbine in the rotational direction while the partial suction air stream entering the turbine chamber impacts the turbine vanes in a direction counter to the rotational direction and is designed to act in a decelerating way. In this way, the intake window for the incoming suction air stream as well as the intake window for the decelerating partial suction air stream are formed with a smaller axial width than the width of the turbine. This is supposed to prevent that portions of the suction air stream remain unused.
The intake window of the partial suction air stream is adjustable with regard to its cross-section so that the desired rotational speed of the air turbine can be adjusted. In this way, a powerful vacuum cleaning tool with rotating brush roller is provided that can be easily adjusted to the momentary application, respectively. A disadvantage is that as a result of the air turbine used for driving a certain design-related noise level will result.